The launch of NASA's Soil Moisture Active Passive (SMAP) mission at Vandenberg Air Force Base (VAFB) in California is scheduled for Thursday, Jan. 29. Liftoff from Space Launch Complex 2 aboard a United Launch Alliance Delta II rocket is targeted for 6:20:42 a.m. PST (9:20:42 a.m. EST) at the opening of a three-minute launch window. If needed, a backup launch opportunity is available on the Western Range on Jan. 30 with the same launch window.

SMAP is the first U.S. Earth-observing satellite designed to collect global observations of surface soil moisture and its freeze/thaw state. High-resolution space-based measurements of soil moisture and whether the soil is frozen or thawed will give scientists a new capability to better predict natural hazards of extreme weather, climate change, floods and droughts, and will help reduce uncertainties in our understanding of Earth's water, energy and carbon cycles.

The mission will provide the most accurate and highest-resolution maps of soil moisture ever obtained, mapping the globe every two to three days from space for a least three years. The spacecraft's final circular polar orbit will be 426 miles (685 kilometers) at an inclination of 98.1 degrees. The spacecraft will orbit Earth once every 98.5 minutes and will repeat the same ground track every eight days.

Prelaunch news conference

Tuesday, Jan 27: The prelaunch news conference will be held at 1 p.m. PST (4 p.m. EST) at Vandenberg Air Force Base. The briefing will be carried live on NASA Television and streamed on NASA.gov. The public can post questions during the briefings via Twitter by using the hashtag #askNASA. The event will also be streamed online.

An ELaNa CubeSat briefing will be held immediately following the prelaunch news conference. NASA will launch three small research satellites for two universities and JPL. More than 100 university students have been involved in the design, development and construction of the CubeSats that are being flown as auxiliary payloads on the SMAP mission.

Presenting the mission science objectives for the ELaNa CubeSats will be:

In conjunction with the SMAP launch, NASA is holding a NASA Social, bringing together mission scientists and engineers with an audience of 70 students, educators, social media managers, bloggers, photographers and videographers who were selected from a pool of 325 applicants from 45 countries. As part of the event, on Jan. 28, a speaker program about the science and engineering of SMAP will be broadcast at 9:30 a.m. PST (12:30 p.m. EST) on NASA Television and webcast at:

Weather and visibility conditions permitting, the launch may be visible from the Greater Los Angeles area by looking to the west.

For photographers: the launch azimuth after liftoff will be 196 degrees.

Following launch, SMAP observatory and mission officials will hold a postlaunch news conference to provide the spacecraft status and discuss its state of health, as well as the status of the ELaNa CubeSats. The event will begin at 9 a.m. PST (noon EST) and will be carried live on NASA Television and www.ustream.tv/NASAJPL2.

NASA television coverage

NASA Television will carry the prelaunch news conference starting at 1 p.m. PST (4 p.m. EST) on Tuesday, Jan. 27. The prelaunch news conference also will be webcast at:

For extensive prelaunch, countdown and launch day coverage of the liftoff of SMAP aboard the Delta II rocket, go to http://blogs.nasa.gov/smap.

A prelaunch webcast for the SMAP mission will be streamed on NASA's website at noon PST (3 p.m. EST) on Wednesday, Jan. 28. To view the webcast and the countdown blog or to learn more about the SMAP mission, visit:

JPL is responsible for SMAP project management, system engineering, mission operations and the ground data system. JPL also built the observatory and its radar instrument. The NASA Goddard Space Flight Center in Greenbelt, Maryland, is responsible for the SMAP radiometer instrument. Both centers collaborate on science data processing and delivery. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida provides launch management. United Launch Alliance of Centennial, Colorado, is NASA's launch service provider of the Delta II rocket.